The following sums were obtained for sample of 1 0 salesmen on intelligence and their weekly scores (where x is the test score and y is the sales). Ex = 600 E y = 40 E xy = 2530

= 38400 = 174 .

i. Fit a simple linear regression model between X and Y (5 marks) ii. Obtain the standard error of the slope estimate , iii. Test the statistical significance of the intercept at 5% level of significance